Will FDA Limit Vicodin Rx?

Until OxyContin (oxycodone) came along in the mid 1990s, Vicodin (acetaminophen and hydrocodone) was the painkiller most often associated with prescription narcotic abuse.

Celebrities such as Brett Favre and Rush Limbaugh were among those who said they were addicted to the drug.

For years the U.S. Food and Drug Administration has resisted stricter controls on drugs such as Vicodin, which contain a mix of opioid and over-the-counter analgesics.

Less Addictive?

Due to the increase in painkiller abuse and overdoses, the Drug Enforcement Administration once again asked the FDA to consider tightening prescribing and other rules on hydrocodone drugs.

Beginning Thursday, the FDA will conduct a 2-day hearing on whether hydrocodone products should be more highly regulated like other narcotics such as OxyContin and morphine, a shift from schedule III (the current classification for Vicodin) to schedule II.

Historically the agency has not supported stricter controls on hydrocodone, saying that doing so could limit patients' access to pain medicine.

It is a stance that has frustrated doctors who are confronted daily with the widespread abuse of prescription opioids in America.

In a briefing document filed before this week's meeting, FDA researchers said that while chronic pain patients taking hydrocodone products might develop moderate or low physical dependence, they would not be expected to develop addiction.

They concluded that hydrocodone products have lower potential for abuse than oxycodone, the narcotic used in opioids such as Oxycontin and Percocet.

"That's just not true," said Jane Ballantyne, MD, a professor of anesthesiology and pain medicine at the University of Washington. "They really don't have the evidence for that."

It is dangerous to think of it that way and to single out opioids such as hydrocodone for relaxed controls, said Robert DuPont, MD, president of the Institute for Behavior and Health, a nonprofit group working to reduce illegal drug use.

DuPont, a former director of the National Institute on Drug Abuse, co-authored a Jan. 16 letter to the FDA, showing that as sales and use of hydrocodone and other opioids have increased over the years, so too have unintentional overdose deaths and hospital admissions for opioid emergencies.

"It (hydrocodone) is a threat to the public health," he said in an interview.

In his letter to the FDA, DuPont said a lot has been learned about the potency and abuse potential of hydrocodone since it first was classified as a schedule III drug 40 years ago.

"Today, we know that this drug is both potent and highly addictive," he and his co-authors wrote. "Updating the classification of hydrocodone ... would be one of the single most important interventions the federal government could implement to bring this raging epidemic under control."

Waiting for Testimony

Douglas Throckmorton, deputy director of the FDA's Center for Drug Evaluation and Research, said the internal analysis done by FDA scientists does not represent the official stance of the FDA.

He said the FDA will not make an official recommendation until taking testimony at the 2-day meeting and getting a recommendation from the advisory panel that scheduled the hearing.

"It's important to give everyone a voice," he said.

At the heart of the controversy is a question that has defied a good answer: Are hydrocodone combination products any less capable of causing addiction and abuse than more strictly controlled opioids such as morphine or oxycodone?

In addition to celebrities, Vicodin has been popular with teenagers. Annual surveys taken over the last decade show that between 8% and 11% of high school seniors have used Vicodin illicitly, compared with about 5% for OxyContin.

One thing is clear: The number of people getting prescriptions for both hydrocodone products and oxycodone products grew throughout the 2000s.

In 2011, 47 million people got a prescription for combination hydrocodone products, compared with 15 million who got a prescription for a combination oxycodone product. Each year, several million people also get prescriptions for single-ingredient oxycodone products. Single-ingredient hydrocodone products are not available in the U.S.

The result: In 2009, the Americans consumed 99% of the 39 tons of hydrocodone used in the world as well as 81% of the 77 tons of oxycodone.

Stricter schedule II status means that fewer prescriptions can be written at one time. For each visit to the doctor a patient can get up to 6 months of prescriptions of schedule III opioids such as Vicodin, versus just 3 months for schedule II drugs. Schedule II drugs also have stricter handling and storage requirements.

But there really are not good data showing that hydrocodone products are less addictive than oxycodone products, said Wilson Compton, MD, division director at the National Institute on Drug Abuse.

Compton said the institute has not taken a stance on whether stricter controls should be put on hydrocodone products. He said it is not a simple decision and the FDA must weigh the abuse potential of the drug against the inconvenience and expense that will result if it is changed to a schedule II.

Fast Buzz?

Many addiction researchers contend that the abuse and addiction potential of an opioid is directly related to how quickly it produces euphoric or pleasant feelings in users.

Research done on drug users shows that there is relatively little difference in how quickly they experience those positive feelings when given hydrocodone, oxycodone and another opioid, hydromorphone.

"The data suggest that the relative potency of these three commonly abused opioids do not differ greatly from one another ...," University of Kentucky researchers wrote in a 2008 paper in the journal Drug and Alcohol Dependence.

A similar finding was reported in a 2009 paper in the same journal in which an oxycodone/acetaminophen product and a hydrocodone/acetaminophen product were tested on volunteers who had a history of drug use.

Most opioids are about the same in their ability to cause abuse, said James Zacny, PhD, a researcher at the University of Chicago and lead author of the 2009 paper.

"From a pharmacology standpoint, I don't think there is a lot of logic to say one is different than the other," he said.

Lynn Webster, MD, president-elect of the American Academy of Pain Medicine, said the issue is complicated and his organization will not be taking an official stand on whether to put stricter controls on hydrocodone.

Webster, a Salt Lake City pain specialist who will speak at the FDA hearing, says his personal experience with opioid abusers suggests they prefer schedule II oxycodone drugs to schedule III hydrocodone drugs, but he acknowledged there is not much good data supporting that belief.

In reality, there probably isn't a great deal of difference between the drugs, he said. And hydrocodone has been the most abused drug in America, he said.

He said if hydrocodone were introduced today as a new drug, it most likely would be schedule II because it produces euphoria in users similar to other schedule II opioids, he said.

Though his organization will not oppose stricter controls on hydrocodone, such a change may cause other problems in delivery and access to care, Webster said.

More nonsteroidal anti-inflammatory drugs may be used, which, in turn, can lead to greater risk of cardiovascular problems, he said.

If greater restrictions are imposed, some doctors may decide to prescribe more methadone, another opioid painkiller. But because many doctors are not well trained in using that drug, there could be more methadone overdoses, he said.

Another possibility, he said, "Docs may choose not to prescribe at all."

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